Back-up slip



oct. e, 1925. 1,556,094 l' H. W. FLETCHER BACK UP SLIP Filed Nov. 23V, 1922 @Ty-f .I

maar carica.

*PATE HAROLD w. ELETCHER, or HOUSTON, TEXAS, AssreNon To HUGHES TOOL COMPANY,

' oT HOUSTON, TEXAS, A CORPORATION or TEXAS.

BACK-UP SLIP.

Application led November 23, 1922. Serial No. 602,916.

T all whom it may @0f/wem Be it known that I, HAROLD W. Fm'ronnn,

al citizen of the United States, residing at' Houston, Harris County, Texas, have invented a certain new and useful Improvement in Back-Up Slips, of which the following is a full, clear, and exact .description, such as will enable others skilled in the art to which 't appertains to make and use the same.

My invention relates to slips for use in the operation of screwing or unscrewing joints in pipe, tubing, sucker rods, etc. It is particularly adapted for oil field work and has its most comm-on application in holding drill pipe in drilling operations, especially in connecting or disconnecting tool joints when the drill stem is being inserted into or withdrawn from the hole.

In breaking joints in drill pipe, tubing and the like, it is customarily necessary to use two wrenches; one for the upper part of the coupling or tool joint and one for the lower portion.

ln drilling operations these wrenches are called breakout and .back-up tongs respectively. Thus the breakout tongs are secured to the upper joint of pipe and heldagainst movement byv bearing against a break-out pin. The back-up wrench is 30, held to rotate with the table of the rotary which, by rotation, will rotate the tongs and the lower portion of the joint thus unscrewing the joint..

ln the vuse ofmy slips, l contemplate holding the lower portion of the joint, and the pipe thereon, by means of a slip or slipstin the rotary table and thus do away with vthe necessity of the back-up tongs. The slip its in a tapered seat in the table about the pipe and not only sustains the weight of the pipe but prevents rotation of the table relative to the pipe.

Another object is to construct a slip which will prevent relative rotation of pipe and rotary and which will be simple and strong of construction so as to stand the rough usage to which itwill besubjected.

Another object is to provide a slip of the character stated which will automatically adjust itself for wear and thus remain in operative conditionfor long periods of time.

Referring to the drawing herewith, wherein' like numerals of reference have been applied to like parts in all views; Figii 1 is a p central longitudinal section throng a rotary table, taken approximately lon the line 1-1 of Fig. 2 and showing my improvedj back-up slip employed therewith. Fig. 2 is a transverse section, on the line 2-2 of Fig. 1 showing the slip and the pipe. Fig. 3 is a perspective view showing one of the jaws. ig. 4 is a top plan view of a'slightly different embodiment of the jaw and Fig. 5 is a front elevation of the jaw shown in ile it is contempla-ted that this type of slip may be usedA in breaking joints in connection with standard rig drilling, or may hold the tubing relative to the casing head in pumping operations, lf have shown, and will describe in this specification, the particular application of my device to breaking joints in drill stem while going into and coming out of the hole, as is frequently necessary in rotary drilling operations. ln Fig. -1 l have shown a drill stem l having thereon a tool joint composed of a lower section 2 `and an upper section 3 by means of which the two adjacent sections of the drill stem 1 are coupled together. This drill stem is shown asprojecting upwardly through the tapered seat 4 formed in the rotary table or ina spider, set in a rotary table. f To hold the pipe suspended in the tapered seatv 4 while the 4two sections of the tool jointvare being uncoupled, l have shown my improved back-up slip. rThis slip is made up of three separate jaws, this being the preerred number; although, it is obvious that a different number might be employed if desired. Each of these jaws is formed with a forward pipe engaging face 5 having transverse teeth thereon inclined upwardly so as to better engage the pipe and to sustain its weight. rfhe slips are tapered on their outer faces at 6 to it within the tapered seat 4, it being obvious that when the. weight of the pipe is engaged with the teeth on the forward side of the slip, said slip will be moved downwardly in the seat and will be wedged firmly into contact with the pipe so as to sustain its weight. I employ a.. handle which-may be made of cable as shown at 7 t0 more conveniently operate the slips.' This type of handle is old in the art andv need not be particularly, described. Y. It is desired to employ this yslip not only to sustain the .weight of the pipe, but to prevent the rotation of the table and the rotary seat relative to the pipe so that the 1F10 f engagement therewith, as 'shown at 11.

thirds the length of the jaw itself.

Within this recess 8 is placed an' approximately triangular tooth 10. One point of the triangle yis presented toward the pipe r Iflor e two remaining corners of the triangularI tooth are presented toward the tapered seat as shown at 12 and the side of the tooth opposite the point 11- istapered downwardly to -conform with the taper in the seat 4.

This side is also vhollowed out somewhat atv 13, to provide space fo a longitudinally ex-` tending pin or rod 4 which is extended downwardly through the upperl and lower ends 4of the recess 8 and is secured in position by means of a cottervpin l5 at the lower end thereof. It will be noted that the recess 8 'is smaller at its forward side and .will thus not perlmit thetooth 10 to move from the recess on ythat side; and the rod or pin 14 will limit its movement outwardly way from the pipe. Thus the tooth has a limited range of movement in all directions but may freely adjust 'itself yto the pipe.

The size of the tooth is such that when the rearward points 12 .bear against the walls of the seat 4, the forward face will engage the pipe with the tooth spaced upwardly from the lower end of the recess. This will allow the tooth to adjust itself vertically withinthe recess to conform with thel shape and the size of the pipe, and also' to take up for wear on the tooth, due to use.' The upper and lo-wer ends of the point 11 upon the tooth are rounded off somewhat as shown at 16 so that the pipe may move slightly-in a vertical direction relative to ,the Atooth without unduestrain upon the said tooth. It is not contemplated that the weight of the pipe will be sustained by the tooth 10, but that it will tendto prevent relative rotation of the pipe and the taperedvseat.

In the operation of this slip, when vthe drill stem 1 is being taken out ofthe hole, the said drill stem will be elevated until the tool joint is at a position spaced upwardly away from the rotary table so that the breakout tongs may enga e Lthe upper portion 3 of the joint. The Tower portion 2 is screwed firmly on the drill stem 1, and if the drill stem is held' securely in the rotary, the upper portion 3`of. the joint may be unscrewed from the lower section 2 thereof. 1 there fore use my slips in the usual manner y'about tooth in the direction of the rotating table.

The forward point 11 of the` tooth will engage the pipe and asl the rearward v*tooth 12 is moved slightly it will cause theforward point 11 to bite into thevpip'e and firmly clamp the pipe within the slip, and further rotation of the table will *carryvthe pipe with 1 it in an obvious'manner.`

In the embodlment of my, invention shown in Figs. 4 and 5, the principle of the inven- 4 tion is the same as injthea,embodimentl just described. The ybody offthe vjaw 6 is formed with horizontal teeth 5 upon the forward face as shown in the previous em-` The upper end ofthe recess 8 bodiment. formed in the jaw is` closed by means of a removable countersunk plate 17 held in place'b means of set screws, 18. The recess 8 1n this modification does not extend completely through the jaw, but` onlya part of theway therethrough so that the rear-v ward corners of the tooth 10 will bear lagainst the walls of the recess, rather than against the walls of the tapered seat .4.-

The tooth 10 is therefore he d in position entirely by, the walls"ofgthe recess 8 in which it loosely The outer wall of the recess 8 is tapered to conform with the taper of the seat.4, the tooth being also tapered on its adjacent side to conform thereto,

thereby givingt vthe tooth 10 lthe' same amount of vertical adjustment along the pipe as in theprevious embodiment. As

ill be apparent, theI rotation o-fV thejaw relative to the pipe in this embodiment will cause the rearward angles 12 of the tooth to bear-[against the rear walls of the recess, andwill force the jawagainst the tapered seat. 4. Tp prevent slipping between the jawand the seat 4, I therefore form longitudinal teeth 19 on the outer surface of the slip. v

In this vform of slip the action of the jaw upon the pipe is practically the same as that described relative `to the rst embodiment. The rotation of the table will carry the jaw with it and will cause the tooth 10 to bite into the -pipe firmly and tend tov force the jaw-more firmly in the taperedseat so that the rotation of the seat andthe jawlwill set up a clamping force to resist rotation relative to the pipeand the rotation of the' rotary seat will thus'carry the pipe with it.

The advantages of my improved form of slip lie in the fact that the usual 'back-up tongs and back-up posts upon the 'ro-tary .may be dispensed with. The addition ot' the vertical tooth within each of-the jaws will prevent rotation of the'pipe relative to the-rotary o-r ofthe rotary relative to the pipe, thus performing the function of the back-up tongs. It will therefore accomplish a' saving of labor and of tools and will be of obvious advantage in drilling operations. Having l thus described my invention, what I claim as new and desire to protect by Letters Patent is:

l. In a deviceof the character described, l

a`- plurality of pipe-engaging slips, transversely arranged teeth on the inner faces thereof, a single vertical tooth loosely mounted in a central recess in each slip, said tooth being 'formed to grip the pipe when said slip is rotated relative to said pipe.

2. In a device of the character described, aplurality of pipel engaging slips, transversely arranged teeth -on the inner faces thereof, a single .upright tooth loosely mounted in a recess in'one of said slips, said tooth being triangular in transversal section and a'dapted to be forced into contact with said pipe when relative rotation of said pipe and -slip is attempted. A

3. In a device of the character described,

a downwardly tapered seat, a plurality of pipe engaging slips in said seat having trans-v verse teeth to engage said pipe, a single angular tooth mounted loosely in a recess in eachof said slips and adapted to bear against said pipe, said tooth being. so shaped and mounted that relative rotation of said lpipe and slip will cause said tooth to grip said pipe and saidseat.

4. In a device of the character described, a downwardly tapered seat, adapted to receive a pipe therethrough, a pluralityl of pipe engaging slips having means to engage and sustain the weightof said pipe, a tooth having a sharp angle presented longitudinally to sald' pipe, said tooth'being loosely mountf' ed in said slipand tapered on the side toward said seat whereby said tooth may ad- ]ust itself to 4said pipe and said seat independently of said slip. i

5. In a deviceof the character described, a downwardly tapered seat, adapted to receive a pipe therethrough, pipe engaging4 slips between said pipe and said seat, a longitudinal angular tooth mounted movably relative to said slips and having engagement with said pipe and said seat and adapted to clamp said pipe in said seat when rotation of one relative to the other is attempted.

6. In a device of the character described,

a pipe engaging slip for rotaries having transverse teeth presented toward the pipe dand 'an .additlonal upright -tooth loosely 'adjustable tooth connected therewith,

T. In a device of the character described,

a pipe engaging slip having a transversely toothed forward face toward the pipe and a tapered face on its outer side, in combination with an approximately,triangular tooth looselymounted in a recess 1n said slip,one

angle of said'tooth being presented toward the pipe and the other angles bearing outwardlv and means to hold said tooth in posi,- tion. i

8. In a device of the character described, a tapered seat adapted toreceive a pipe, a pipe. engaging slip` tapered on its outer face to tit said sea-t` a vertically extending movable pipe-gripping tooth on said slip adapted to seize said pipe and said seat as said' slip is rotated with said seat relative to the pipe and thus act to resistl said relative rotation.

f). -In a device of the character described, a dmvnwardly tapered seat having a jointed .member extending longitudinally through the same. a slip having its inner face trans# versely toothed to engage said member and its outer face tapered to fit, said seat, and a movably mounted -member on said slip adapted to resist rotation of said jointed member relative to said seat.

l0. -In a device of the character described, a downwardly tapered seat having a jointed member extending longitudinally through the same, a slip having its inner face transversely toothed to engage said member and its outer face tapered to fit said seat, and a tive rotation of said member and said seat. l l12. In a device of the character described,

an upright separatelyl said tooth having sharp edges thereon adapted' a pipe engaging slip,

to engage the work and se`t up a force tending to resist rotation of the slip relative to the Work.

In testimony Whereof,I hereunto attix my signature, this the 20th day of November, a. D., 1922.

HAROLD W. FLETCHER. 

